| 摘要 |
PROBLEM TO BE SOLVED: To detect which LEDs are disconnected without lighting the LEDs.SOLUTION: A control device is provided including a plurality of LED arrays connected in parallel to one another, each of the plurality of LED arrays including LEDs and resistance elements 5 connected in series to the LEDs and having resistance values different from each other, a first switching circuit 6 and a second switching circuit 7 interposed between the LED arrays and a power source 2, a capacitor C1 having one end connected to the first switching circuit and the other end connected to the LED arrays, and a voltage detection circuit 3 having one end connected to the other end of the capacitor. In the control device, the first switching circuit is made a cut-off state, the second switching circuit is electrically conducted to supply voltage for lighting the LEDs and the LEDs are lighted, the second switching circuit is made a cut-off state, the first switching circuit is electrically conducted to supply rectangular wave pulse voltage having a pulse width not to light the LEDs, the presence or absence of disconnection of the LEDs in the LED arrays is detected on the basis of a voltage value read from the voltage detection circuit, and the disconnected LED arrays are specified. |
